See it this way. A master player has knowledge about for example typical pawn structures that form up in mid game and that have this and that advantages and disadvantages, tactical benefits and risks in the endgame. Consider you play against him, and you reach a position in the 20th move. He sees these structures and knows what they mean, and he can by that make an educated assessement on which structure to avoid and which one he wants to realise. He knows that the pattern in structure A gives him a superior advantage once material is reduced and end game is entered, but structure B is hard to turn out as a victory. He knows that - although he can not calculate from the 20th move right down to the 55th move. You, on the other hand, avoid to raise your theoretical knowledge, and you can calculate only 2, at best 3 moves in advance. You only see that nice sqaure for the queen two moves from now on, and choose to go with the according variation - the same variation that he is happy with for the reason named before. By that you give him the pawn structure that seals his victory, because you do not know what you are doing by focussing on the nice field for the queen only. And although you consider to have made a good move, you are already doomed, and in the end you even do not know why you have lost - it is like magic to you.
Why do you think has the revolution (and that is what it has been, imo) in chess software programming focused not on just increasing calculation speed and leading the brute force strategy (Shannon A) to deeper calculation depth? Why have they tried so hard to "teach" computer tactical knowledge so massively in the past 15 years? Why does none of today's top programs base on brute force alone anymore, but are all more or less "knowledge-oriented" - even former traditional brute force-extremists? And how could you ever hope to correctly assess a given position, if you have no knowledge about strategy and tactics that serve as a standard by which you compare the given position? Even a stupid, non-intelligent computer needs to have such standards for comparison and reference.
